Alright, let's work through 1681 times 2505 step by step
1681 × 2505 = 2505 × (1681)
+ 2505 × 1 yielding 2505
+ 2505 × 80 giving us 200400
+ 2505 × 600 giving us 1503000
+ 2505 × 1000 which equals 2505000

= 4210905
